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Biomedical subjects

M Prager

Publications and source records attributed to M Prager.

At least 19 recordsLinked to original sources
PubMed1997

[Abdominal aortic aneurysm: surgery, indications, technique, outcome].

The fate of a patient with an abdominal aortic aneurysm] (AAA) is influenced by the risk of rupture and embolism. When the indication for operation is considered, individual associated risk factors have to be taken into account. With regard to the literature, the following recommendations concerning indication for surgery can be given: emergency surgery for symptomatic or ruptured aneurysm; elective surgery: aneurysms 5 cm diameter or growing AAA 5 mm/year, patient with acceptable individual risk for operation; asymptomatic aneurysms less than 5 cm in diameter, without growth in patients aged over 75 years and/or considerable perioperative risk should not be operated on: sonography should be done 3-monthly as a continuing control. Finally the results in our institution are presented for elective surgery: 30-day mortality 3.5%, AAA with rupture, no shock: 20%, ruptured AAA with shock 47%, respectively.

Aortic Dissection↗
PubMed1997

[Acute mesenteric ischemia].

UNLABELLED: Acute mesenteric ischemia is a life-threatening vascular emergency. A retrospective analysis of our patients was performed to describe the development of the various procedures of diagnostic assessment and treatment between 1970 and 1996, to show the influence on survival and to define recent standards. PATIENTS: Between 1970 and 1996, 145 patients, 75 male and 70 female, suffering from acute mesenteric ischemia, have been treated at the Department of Surgery-University Hospital Vienna. RESULTS: In most cases AMI was caused by arterial embolism (64.1%, n = 93) followed by arterial thrombosis (27.6%, n= 40). Venous thrombosis (3.5%, n = 5) and non-occlusive AMI (4.8%, n = 7) were rare events. Serum lactate level has been determined routinely in all patients having been admitted with acute abdomen since 1984 and turned out to be positive in 81.2% (mean value 9.81 (3.21-22.3) mmol/l). Abdominal x-ray gave only in some individual cases special hints to the advanced intestinal gangrene. Abdominal sonography led to the correct diagnostic assessment in 52 patients (= 35.8%). Angiography was in 92% conclusive for the diagnosis. Abdominal CT led to establish the correct diagnosis in > 80%. Our series with revascularisation (thrombectomy/embolectomy or bypass) has resulted in 73.8% patient survival with intestine having been maintained in the most favourable cases. CONCLUSIONS: Early diagnostic assessment and treatment are decisive for survival. Abdominal-CT, angiography and serum-lactate constitute quick and reliable means to provide diagnosis and to judge the stage of AMI in addition to meticulous examination of patients' history, symptoms and physical conditions.

Acute Disease↗
PubMed1994

Acute-phase hepatocytes regulate liver sinusoidal cell mediator production.

BACKGROUND: Overproduction of liver sinusoidal cell (LCS) mediators in response to endotoxemia or gram-negative infection that follows tissue injury may contribute to hepatic dysfunction. OBJECTIVE: To better define the role of hepatocyte-derived acute-phase reactants in the regulation of sinusoidal cell mediator production following sequential insults, we tested the hypothesis that interleukin-6 (IL-6) prestimulation alters hepatocyte regulation of lipopolysaccharide (LPS)-stimulated sinusoidal cell tumor necrosis factor (TNF), IL-6, and nitric oxide production. METHODS: Hepatocytes and LSCs were isolated from Wistar rats, and in vitro responses were compared between LSCs alone and hepatocyte-LSC cocultures. Cocultures and LSCs alone were sequentially stimulated with IL-6 (5000 U/mL) then LPS (dose-response), and culture supernatants were analyzed for TNF (L929 cytolysis), IL-6 (7TD1 proliferation), and nitric oxide (Griess reaction). Induction of acute-phase protein synthesis by the stimulation of hepatocytes with IL-6 and dexamethasone (0.1 mumol/L) was assayed by methionine radiolabeling and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Coculture levels of messenger RNA for TNF-alpha and IL-6 were examined by RNA extraction and reverse transcriptase polymerase chain reaction with specific primers. RESULTS: Interleukin-6 and dexamethasone signal hepatocyte acute-phase protein synthesis. Prestimulation of cocultures, but not of LSCs alone, with IL-6 inhibits LPS-stimulated IL-6 and nitric oxide production significantly. Bioactivity of TNF is reduced to a lesser extent. Polymerase chain reaction analysis demonstrated similar levels of TNF and IL-6 message following sequential stimulation. CONCLUSIONS: Interleukin-6-stimulated acute-phase hepatocytes limit LPS-stimulated coculture cytokine bioactivity and nitric oxide production. This hepatocyte response may provide a local counterregulatory mechanism to limit LSC-mediated injury.

Acute-Phase Proteins↗
PubMed1994

Cytokine-induced expression of nitric oxide synthase in C2C12 skeletal muscle myocytes.

Nitric oxide (NO) is an important mediator of diverse physiological and pathological responses. To determine whether NO production can be induced in skeletal muscle, we stimulated C2C12 mouse skeletal muscle myocytes with putative inducers of nitric oxide synthase (NOS). Neither lipopolysaccharide (LPS), interleukin-1 alpha (IL-1), tumor necrosis factor-alpha (TNF), nor interferon-gamma (IFN) was able to stimulate nitrite production by C2C12 cells when administered alone. However, combinations of IFN with either TNF or IL-1 resulted in significant nitrite production; simultaneous stimulation of cells with all three cytokines resulted in significantly increased nitrite production compared with any combination of two cytokines. Northern analysis of RNA obtained from stimulated C2C12 cells revealed induction of a single mRNA band that precisely coincided with the mRNA band of mouse macrophage-inducible NOS (iNOS). Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis followed by sequencing of the 5' 765 bases of the skeletal muscle iNOS cDNA demonstrated exact homology with mouse macrophage iNOS. These findings indicate that combinations of cytokines stimulate NO production in skeletal muscle cells via induction of the macrophage-type iNOS gene.

Amino Acid Oxidoreductases↗
PubMed1994

[Surgical therapy of acute thrombosis of leg-pelvic veins].

A series of 213 consecutive patients suffering from acute iliofemoral vein thrombosis who underwent venous thrombectomy is analyzed. Surgery was performed from an inguinal approach with a Fogarty-balloon-catheter from the proximal vessel and by bimanual exprimation from the femoral and popliteal veins. Post-operative oral anticoagulation treatment was attempted whenever possible. Long term results obtained in 130 patients after a median follow-up of 78 months (44% free of symptoms, 33% PTS [postthrombolic syndrome] I, 15% PTS II, 8% PTS III) showed a significant correlation to the duration of preoperative anamnesis: < or = 5 days: 64% free of symptoms, > 5 days: 34% free of symptoms, the rate of PTS III was equally distributed in the group with long (< or = 5 days) and short (> 5 days) anamnesis (8 and 9% respectively). Postoperative Dicumarol-therapy decreased the rate of severe PTS: 28% without, respectively 10% with therapy. If the medication was cancelled aggravation of the clinical symptoms in 1 third of the patients was observed. Venous thrombectomy is an important treatment option in patients with contraindications to thrombolytic therapy. With patients younger than 65 years and short anamnesis functional results are acceptable, high risk patients (severe cardiac disease and previous pulmonary embolism) should be treated with medical therapy only.

Female↗
PubMed1993

Thermoregulatory responses to hyperthermia during isoflurane anesthesia in humans.

The authors tested the hypotheses that isoflurane anesthesia increases the threshold for sweating but minimally decreases the gain (sensitivity) or maximum intensity of this response and that thermoregulatory responses to hyperthermia are similar in anesthetized men and women. Sweating in response to core hyperthermia was studied in five men and five women during 0, 0.8, and 1.2% end-tidal isoflurane anesthesia. Thigh sweating was quantified by measuring gas flow, relative humidity, and temperature passing over a known surface area. The distal esophageal temperature triggering sweating was considered the sweating threshold, and gain was defined as the core temperature increment required to increase sweating rate from 25 to 75% of maximum observed intensity. The sweating threshold increased linearly with isoflurane concentration from 36.6 +/- 0.1 to 38.1 +/- 0.1 degrees C in the men and from 37.1 +/- 0.3 to 38.3 +/- 0.2 degrees C in the women. The thresholds were significantly higher in women than in men. Gain and maximum sweating intensities were similar at each anesthetic concentration and in men and women. These data indicate that isoflurane anesthesia significantly increases the threshold triggering thermoregulatory sweating but that gain and maximum sweating rate are relatively well preserved.

Anesthesia↗
PubMed1992

A decade of oral anticoagulant treatment to maintain autologous vein grafts for femoropopliteal atherosclerosis.

To determine whether long-term oral anticoagulant treatment was effective in improving graft performance and preventing major amputation following vein bypass surgery for femoropopliteal atherosclerosis, a clinical trial was conducted in one single center and continued during 10 years. After 130 patients had electively received a femoropopliteal vein graft, they were randomly assigned to a therapy group (treatment with phenprocoumon [n = 66]) or to a control group (n = 64) that remained without any anticoagulant treatment. Primary end points of the study were graft reocclusion and limb loss. The median durations of primary patency and limb salvage were significantly longer for treated patients than that for controls. In addition, survival in the therapy group was longer. Following autologous vein bypass surgery in the treated group, the results were superior in terms of graft patency, limb salvage, and survival.

Administration, Oral↗
PubMed1992

Dacron versus polytetrafluoroethylene for Y-aortic bifurcation grafts: a six-year prospective, randomized trial.

BACKGROUND: A prospective, randomized trial was conducted to compare Dacron with expanded polytetrafluoroethylene (ePTFE) in reconstructive aortoiliac surgery. No comparable trial with a prospective, randomized design with a comparable number of patients or an equal long-term follow-up period can be found in the literature. METHODS: Between 1984 and 1989, 165 patients were randomized for either Dacron or ePTFE on the basis of age, sex, indication for surgery, diabetes, nicotine consumption, runoff, and operative approach. The two groups were well matched for randomization criteria, as well as the incidence of aneurysms. RESULTS: No statistically significant difference was found between the two graft materials in terms of patency rates (corrected 3-year patency rates: Dacron = 95% vs ePTFE = 95%; Breslow, p = 0.83; Mantel-Cox, p = 0.74). Subgroup analysis comparing long-term patency rates of the two graft materials and relating them to poor runoff, good runoff, aneurysms, and arterial occlusive disease also failed to show any significant differences between ePTFE and Dacron. Early graft failure (n = 6; 3.6% of the patient population; p = 0.045) and severe abdominal graft infection (n = 3; 1.8% of the total population) were seen only in ePTFE grafts. However, these did not affect the corrected long-term patency rate of ePTFE grafts. There were five late graft failures with PTFE (3.0%) and four with Dacron (2.4%). CONCLUSIONS: Graft materials currently available for aortoiliac repair were comparable in terms of corrected long-term patency rates. The alleged advantages of PTFE were not confirmed by our data. PTFE grafts were associated with a higher rate of complications, and more redo operations were required to duplicate the results obtained with Dacron.

Aorta↗
PubMed1991

[The status of carotid artery surgery today: technique, indications, results].

Carotid artery endarterectomy (CAE) is a surgical standard procedure today. The indication is the symptomatic patient (Stage II) with transient ischemic attacks (TIA) and stenosis of the internal carotid artery (ACI). Data of several studies have yielded a highly restrictive policy toward operative procedures in asymptomatic patients (Stage I) with carotid bruit or ACI-stenosis. Furthermore there emerged wide consensus, that patients with frank stroke (Stage III) should not be operated upon. As diagnostic procedures highly advanced non invasive procedures came up during the last decade, as well as computerized tomography and digital subtraction angiography. The operative procedure is performed in general anesthesia with controlled hypertension during the clamping period (n = 650). Perioperative results without using a shunt are not different to those with a shunt. During the last 5 year period our results yielded a 1% perioperative central permanent neurological deficit rate (CPNDR) and a 1% operative mortality. During a 51 months median observation period 1.5% presented again with transient ischemic attacks-with TIA; 0.6% developed a stroke and 2.2% deceased by cerebral complications yielding at totally 4.3% long term complication rate. The annual rates are 0.3%, 0.1% respectively 0.5%, totally 0.9%. In conclusion CAE can be offered as a safe surgical stroke preventing procedure in symptomatic TIA patients with ACI stenoses in our institution. Perioperative as well as long term results are yielding a high standard and are clearly better than those without operation.

Carotid Artery Diseases↗
PubMed1991

[Effect of postoperative aggregation inhibiting therapy following carotid thrombendarterectomy on patient survival. Analysis after more than 15 years follow-up].

The patients in the clinical series as well as in the group with preoperative known cardiac risk receiving postoperative ASA medication yielded a significant better long-term survival results. ASA prolongs long-term survival after carotid endarterectomy. A postoperative ASA-therapy decreases the incidence of lethal cardiac complications.

Aspirin↗
PubMed1990

The many faces of AIDS: opportunities for intervention.

Social and cultural issues may have a profound impact on different populations' responses to the AIDS epidemic. To maximize their own effectiveness, clinicians need to be aware of special needs and concerns.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Antiplatelet therapy following carotid bifurcation endarterectomy. Evaluation of a controlled clinical trial. Prognostic significance of histologic plaque examination on behalf of survival.

To determine whether antiplatelet therapy following carotid bifurcation endarterectomy influences postoperative survival and whether signs of progression in the plaques harvested at the time of surgery might be a prognostic indicator, a controlled clinical trial was undertaken. During 1982 to 1985, 66 patients were recruited, operated on (carotid endarterectomy) and assigned, using the method of adaptive randomisation to the therapy group (n = 32) receiving 1.0 g acetylsalicylic acid (ASA) per day, starting day two prior to surgery, or to the control group (n = 34), which remained without antiplatelet medication. The plaques harvested at the time of surgery were processed using standard histopathological methods and examined "blindly" by light microscopy for signs of arterio-sclerotic progression. The final endpoint was patient survival. The last assessment of the participants survival status was done by June 1989. During follow-up, 20 patients died, six in the treatment group and 14 in the untreated group, the difference being statistically significant (P less than 0.013 Breslow, P less than 0.029 Mantel). In 27 instances the histo-pathological examination showed signs of progression. In this subgroup ASA yielded a significant prolongation of patient survival (P less than 0.017 Breslow, P less than 0.048 Mantel). In the remaining patients no signs of cellular infiltration were evident and no influence of ASA on patient survival was demonstrable (P less than 0.503 Breslow, P less than 0.390 Mantel).

Aged↗
PubMed1990

Antiplatelet treatment prolongs survival after carotid bifurcation endarterectomy. Analysis of the clinical series followed by a controlled trial.

To examine the role of antiplatelet drugs in the secondary prevention of arteriosclerotic arterial disease following carotid endarterectomy, a clinical series (n = 252) was analyzed. Based on these results a prospective randomized trial was initiated, comparing the effect of antiplatelet drugs (acetyl-salicylic acid [ASA] 1000 mg/day) versus untreated controls. In both investigations patient survival was the primary end point. A cardiac risk (n = 91) implied a significant reduction in patient survival (p less than 0.019 Breslow, p less than 0.052 Mantel). Antiaggregating drugs prolonged survival in the collective series (p less than 0.0001 Breslow, p less than 0.0002 Mantel) and in the subgroup of patients with cardiac risk (p less than 0.014 Breslow, p less than 0.020 Mantel) as well. In the prospective trial 66 patients were recruited, receiving ASA (n = 32) versus no therapy (n = 34). During follow-up 15 patients died, 4 in the treatment, and 11 in the control group. Between both groups there was a significant difference in the probability of survival (p less than 0.021 Breslow, p less than 0.048 Mantel).

Aspirin↗
PubMed1990

Patency rate of implantable devices during long-term intraarterial chemotherapy.

Intraarterial implantable drug delivery systems have been considered as an alternative method for treating patients with unresectable liver malignancies. However, catheter problems with external implanted devices have resulted in limited application of chemotherapy. The introduction of subcutaneous devices offers an opportunity for long-term locoregional chemotherapy. Twelve external intraarterial catheters were implanted into 12 patients and 52 subcutaneously placed devices into 51 patients, all with various hepatic malignancies. Retrospective analyses comparing those two intraarterial systems were conducted taking into account the function and complication rate (hepatic artery thrombosis, infection, leaking, hemorrhage, and dislocation). The follow-up time for the external system was two to eight months (median five weeks), the thrombosis rate 33.3%, and the infection rate 25%. One instance of severe bleeding from the hepatic artery occurred during chemotherapy. One catheter dislocated. For the subcutaneously implanted intraarterial devices the follow-up time was five to forty-one months (median sixteen months), the thrombotic complication rate 17.3%, and the infection rate 7.6% (all patients with simultaneous bowel surgery). Catheter dislocation one year later required reimplantation; in 1 patient therapy had to be discontinued because of a catheter leak. The overall function rate was 71.3% with a median follow-up time of eight months. Anticoagulation therapy for subcutaneously implanted devices starting from the beginning of intraarterial chemotherapy is recommended to achieve long-term patency. No implantation should be preformed simultaneously with bowel surgery. The subcutaneously placed intraarterial devices had a higher function rate and were available for a longer period as compared with external implanted catheters.

Equipment Failure↗